The brain is divided into two hemispheres, then further subdivided into four sections, called lobes: the frontal lobe, the parietal lobe, the temporal lobe, and the occipital lobe. Each hemisphere and lobe is related to a different type of behavior or different mental processes. This is what we refer to as localization of function.
The frontal lobe is related to many different mental processes and functions that are recognized as being uniquely human. These include functions like the control of movement of our bodies, long-term memory, planning, reasoning, and even judgment.
Research exploring damage to the frontal lobe has proven to assist in the discovery of the impact that the frontal lobe has on changes in an individual's personality and behavior.
A famous psychological case involves studying a man who survived an accident in which a tamping rod (a long thin rod with a spike on one end) went through his brain, causing severe damage.
In 1848, a rod shot through the brain of Phineas Gage, specifically through the frontal lobe, the prefrontal cortex.
His friends noted that there were specific changes within his behavior and his personality as a result. Phineas became a lot more quick-tempered and impatient. He was also very indulgent in behaviors that were less acceptable.
Prior to the accident, Phineas was very hardworking and responsible. However, after the accident, he had taken up cursing, drinking, gambling. In addition, there was intellectual damage, and he couldn't complete work or plan for things.
This case demonstrated that the frontal lobe must be related to a lot of those behaviors. This led to much of the initial scientific development about localization of function and the different parts of the brain related to different behaviors and processes.
Another aspect of the frontal lobe, and damage to it, involves the surgical procedure called a lobotomy. The frontal lobotomy was popular in the U.S. during the 1940s.
It involved disconnecting or removing certain sections of the prefrontal cortex of the frontal lobe. This was meant to deal with a lot of severe mental disorders, especially in difficult individuals.
A lobotomy created severe changes in a person's activities and their personality. Individuals were rendered very docile, and the surgery often reduced them to a vegetable state, or comatose. Eventually, it was abandoned because of cruelty. Thankfully, new, more humane sorts of procedures were introduced.
The first area to discuss in the frontal lobe is the prefrontal cortex. The prefrontal cortex is the foremost part in the front of the frontal lobe. It's basically the first half area of the frontal lobe, going all the way up to the front.
The frontal lobe is responsible for a person's sense of self (e.g., self-awareness, impulse control, and emotions). You can see that the examples of Phineas Gage and the lobotomy concern damage specifically to the prefrontal cortex, which lead to changes in personality.
The prefrontal cortex is also related to reasoning and planning. It is responsible for higher-level cognitive abilities specific to humans.
Another important aspect of the frontal lobe includes the association areas, which comprise the rest of the frontal lobe, moving up towards the parietal lobe. Those areas help to process information and relate to the formation of memory. Much of the sensory information coming into a person is processed in these association areas.
One of the association areas that is important to language production specifically is Broca's area. Broca's area is named for a French neurosurgeon named Paul Broca.
Dr. Paul Broca noticed that patients with brain damage to this area of the brain were able to understand words, but could not actually produce speech. This is a condition called Broca's aphasia, where subjects are unable to produce speech even though they understand what other people are saying to them.
Specifically, this is an issue related to motor production and includes problems with grammar and pronunciation. Any kind of language the person is able to produce is very difficult to understand.
The final area of the frontal lobe to discuss is the primary motor cortex, which is the little area bordering the parietal lobe. This area in particular is related specifically to movement and the control of the body's muscles.
The primary motor cortex is arranged in such a way that larger areas of the prefrontal cortex are devoted to more important and specific, or more sensitive, areas of the body.
EXAMPLE
Hands have a much larger corresponding area in the brain because they're very sensitive and we need to manipulate them in complex ways. Similarly, the face and the tongue have larger areas of the prefrontal cortex devoted to their function because they are very sensitive and contain minute areas that people want to be able to control with a lot of precision.Source: This work is adapted from Sophia author Erick Taggart.
